Recently, with the development of touch input technologies, a touch input device often includes touch buttons for user input in order to control electronic devices (i.e., control devices). For example, a touch input device for a vehicle may be implemented in a smart key and have a function touch button, such as a smart key button for door opening and closing control.
Such a touch input device may have a touch electrode configured to perform a wake-up function and may also have a microcontroller unit (MCU) for detecting a capacitance formed by the touch electrode. In this case, when a capacitance increases to a reference value or more, the function touch button may recognize a touch input of a user.
However, a conventional touch input device for a vehicle can mostly remain in a power-saving mode due to a limited battery lifetime. Although a user can operate an electronic device (i.e., control device) for a vehicle in various environments, since the electronic device is usually maintained in the power-saving mode, the conventional input device for vehicle may not detect a change in capacitance detected by a function touch button.
In addition, when capacitances generated by a function touch button are sharply increased or decreased by external environmental changes such as humidity and temperature, the conventional touch input device for a vehicle recognizes the increase or decrease as a touch input as soon as it wakes up, even though there is no user touch input. Meanwhile, the conventional touch input device can fail to recognize a user touch input when it occurs.